From their website:
Since 1958 the Naval Sea Cadet Corps has been committed to providing American youth with a drug and alcohol free environment to foster their leadership abilities, broaden their horizons through hands-on training and guide them to becoming mature young adults.
Sea Cadet organizations exist in most of the maritime nations of the world. Recognizing the value of these organizations in educating youth in maritime matters, the Department of the Navy requested the Navy League of the United States to establish a similar program for American youth. The Navy League agreed to do so and formally established the Naval Sea Cadet Corps (NSCC) and Navy League Cadet Corps (NLCC) in 1958. Recognizing the importance and benefits of the NSCC, Congress on September 10, 1962 federally incorporated the Naval Sea Cadet Corps under Public Law 87-655 (36 USC 1541).
Today, the NSCC has formed partnerships with organizations such as the Foundation for Teaching Economics and the Flying Midshipman Association to offer cadets broader opportunities in areas of leadership and aviation. The NSCC also took an active part in the creation of the International Sea Cadet Association (ISCA). The ISCA is an association of Sea Cadet Corps from around the world, whose main objective is to facilitate exchanges of cadets between member countries.